Abstract

LOBATO-ORTIZ, Ricardo et al. Criteria to choose the best tester of the general combining ability for grain yield of maize inbred lines. Agrociencia [online]. 2010, vol.44, n.1, pp.17-30. ISSN 2521-9766.

In a maize (Zea mays L.) breeding program by hybridization it is important to have a reliable and efficient tester for the general combining ability (GCA) of maize inbred lines. With the aim to contribute more experimental evidence relative to the identification of the best tester of GCA of maize inbred lines, in this study 50 S₁ lines derived from the Compuesto Universal original (original variety), plus four lines of high and four of low GCA derived from populations of Xolache and Mex. Gpo. 10 were used. The S₁ lines were crossed with three testers: a line of low GCA (P1), a line of high GCA (P2), and the original variety (P3). The hypothesis was that the line of low GCA is the best tester. The criteria to evaluate the testers were: 1) the phenotypic and genotypic variation of top crosses (line × tester); 2) the classification of the eight lines of known GCA, with each of the three testers, 3) the coefficient of divergence (CD), 4) the effect of the tester, effect and variance of interaction line × tester. The variable studied was the average yield of ear by plant. Based on the mentioned criteria, the best tester was the line of low GCA compared to the line of high GCA and the original variety; besides, the original variety was also a good tester, but with less discriminatory value than the low GCA line.

Keywords : Zea mays L.; GCA; high and low GCA lines; top crosses; testers.